Trophic Levels, Energy transfer and...
Transcript of Trophic Levels, Energy transfer and...
Vocabulary
Trophic Levels – is the position an
organism occupies in a food chain. It
refers to food or feeding.
Apex predator – top level predators with
few or no predators of their own.
Food Chains
The energy flow from one trophic level to the
other is know as a food chain
Producers are at the first TROPHIC LEVEL
Primary Consumers are the SECOND TROPHIC
LEVEL
Secondary consumers are at the THIRD
TROPHIC LEVEL
Food Web
Most organisms eat more than JUST one organism
When more organisms are involved it is know as a FOOD WEB
Food webs are more complex and involve lots of organisms
Food Webs
Food webs show
ALTERNATIVE PATHWAYS
other possible pathways
through which an
organism can obtain
energy
Trophic Level Producer, primary
consumer, secondary
consumer, tertiary
consumer?
Grass
Mouse
Grasshopper
Frog
Owl
Hawk
Trophic Level Producer, primary
consumer, secondary
consumer, tertiary
consumer
Grass 1st Producer
Mouse 2nd Primary consumer
Grasshopper 2nd Primary consumer
Frog 3rd Secondary
consumer
Owl 3rd and 4th Secondary and
tertiary consumer
Hawk 3rd Secondary
consumer
Transfer of EnergyWhen a lion eats a zebra, it does
not get all of the energy from the
zebra.
Energy lost is usually in form of heat
Energy lost from chain “link” to “link”
is significant!
from grass to sheep, loss is about
90%!
10% Original
Energy! 1% Original
Energy!
100% Energy
Available
HEAT
90%
HEAT
90%
Energy lost from one trophic level
(energy level) to the next level can be
represented by a pyramid
PRODUCERS
1 CONSUMERS
2 CONSUMERS
3
CONSUMERS
4⁰CONSUMERS
Each level above only gets 10% of the energy from below
Ex: 10,000 J of producers (plants) only give 10% of energy to primary consumers
1,000 J to primary consumers (snails, minnows, dragonflies)
100 J to secondary consumers (small fish)
10 J to tertiary consumers (big fish)
1 J to quaternary consumers (fish hawk)
Three hundred trout are needed to
support one man for a year. The trout, in
turn, must consume 90,000 frogs, that
must consume 27 million grasshoppers
that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist
(1971)
Usually no more than 5 trophic
levels since 6th level would have
very little energy to keep it alive
Ecological Pyramid
• Which level has the most energy?
• Which level has the most organisms?
• Which level has the least organisms?
• Which level has the least energy?
Pyramid of Numbers
• Shows the numbers of individual organisms at each trophic level in an ecosystem.
tertiary
consumers
secondary
consumers
primary
consumers
producers
5
5000
500,000
5,000,0005,000,000producers
• A vast number of producers are required to support even a few
top level consumers.